Improvement in saw-sharpening device



,Staten ateut i @fthe i 'J'AMlSON H. HARRISON, OF BOSTON, MASSACHUSETTS..

' Leens Patat No. 59,042, dated April 20,1869.

IMPROVEMENT IN SAW-SHARPENING DEVICE.

The Schedule referred to in these Letters Patent and making part of the same.

To all Iwhom fit may concern Be it known that I, J Muses H. HAnmsoN, of Boston, in the county of Suffolk, and State of Massachusetts, have invented a certain new and useful Device for Sharpening Saws; and I do hereby declare that the following is a full and exactrdeseription thereof, reference being had to the accompanying drawings, and to the letters of reference marked thereon.

To enable others skilled in the art to make and use my invention, I will proceed to describe its nature, construction, and use.

The nature of my invention consists in forming spiral grhnling-wheels, so that, when combined with a suitable guide, they shall grind the teeth of the saw, and at the same time shall move the saw, so that each tooth may come in contact with the wheels, and he properly sharpened.

Construction.

Figure 1, of the drawings, represent-s an elevation of my Sharpener.

Figure 2 is a cross-section ofthe device for guiding the saw, and keeping it in position, so that the grinding-wheels C O, tig. l, may act upon it.

A B B is a frame, which serves as a guide for the saw, and asa hanging for the grinding-wheels, and the gear for driving the same. A

C and C', he'. 1, are the g1'i1nli1ig\\'lleels, and will be more fully described hereafter.

E and Eare two hovelled gears, one attached to the driving-shaft. of the wheel O, and the other attached to the driving-shaft ofthe wheel O'.

I) is a lievelled gear, which ma) be operated by thc crunk-handle H,and which actuates,through the gears E E', the grimling-wheels C O', causing them to revolve in opposite directions.-

The plate Bis hinged to B', as represented in iig. 2, and serves, together' with B and the adjustable plate 1, as a guide to keep the saw in the proper position to he acted upon by the grinding-wheels C.

l, fig. 1, is a spring, which brings a sutlcient pressure to bear upon B, and thus upon the saw G, to hohl it in position, and yet allow the saw to pass freely through the guide. i

rlhe wheels C C', have screw-threads, n o n o', and p q p q', cnt upon them, the pitch ofthe thread being cunal'to twice the pitch ofthe saw-teeth; or, in other words, equal to the length of two of the teeth, while the periphery of the threads is inclined, to correspond with the inclination ofthe teeth ofthe saw, as shown in fig. 1. Those threads are either provided with emery, or have tile-teeth out upon them; or the wheels themselves may be made of stone, with threads cu't upon theln, so that when made to revolve, they will grind the teeth of the saw.

The griluling-t-ln'emls and wheels are so arranged that the threads on C take alternate teeth with the threads on C, and, since O' revolves in an opposite direction to C, cach alternate tooth will have an opposite shear, to agree with the set of the tooth.

The drawings represent my invention when used with a hand-saw, but if I wish to apply my grindingwheels to other kinds of saws, I have simply to provide suitable guides.

lhe grhuling-wheels C O serve a double purpose.

-They grind the tooth, and, as they revolve, cause the saw to slide along, in other words, to feed itself.

I do not claim the guides B B, nor the propellinggear l() E, but

What I do claim as my invention, and desire to secure by Letters Vateut of the United States, is-

'lhe saw-sharpening wheels O and C', arranged to operate as described, and for the purpose setforth. g JAMISON H. HARRISON. fitnesses WILLIAM-Epson, A. HUN BERRY. 

